The present invention relates to a method for preparing a heat-sensitive recording material in which a plastic film or synthetic paper is used as the base sheet, particularly to a method in which a protective layer can be formed on the recording layer without generating a bar-line, streak or scratch.
There have been well-known heat-sensitive recording materials utilizing the colorforming reaction between a colorless or pale colored basic chromogenic material and an organic or inorganic color developer, in which the two colorforming materials are thermally contacted each other to produce recorded images. These heat-sensitive recording materials have been used not only as the recording medium of heat-sensitive facsimiles and heat-sensitive printers, but also in the other various fields, such as magnetic heat-sensitive recording system, POS (point of sales) system, tickets, prepaid cards, commutation tickets and the like.
As described above the application has been broadened, and accordingly it has been increased to form a protective layer on the recording layer to improve the retainability of the recorded images. Further, there have been used in many cases as the base sheet not only paper but also such a sheet superior in shelf life as a plastic film or synthetic paper.
However, when a coating composition is applied on a heat-sensitive recording layer of a heat-sensitive recording material, in which a plastic film or synthetic paper is used as the base sheet, to form a protective layer, troubles such as bar-line, streak and scratch easily occur and quality of the product is very lowered. Accordingly, it is necessary to carefully control preparation and/or application of the protective coating composition.
Therefore, it is an object of the present invention to provide a method for producing a heat-sensitive recording material in which a film or a synthetic paper is used as the base sheet, without generating a bar-line, streak or scratch even though a protective layer is formed on the recording layer.